Method of supplementing the frictional resistance of relatively movable members



J. M. CRAWFORD 1,833,415 SUPPLEMENTING THE FRICTIONAL RESISTANCE LEMEMBERS 1928 OF RELATIVELY MOVAB Filed July 2.

Jamesf, rcurfard,

Nov. 24, 1931. v METHOD oF Patented Nov. 24, 41931 I f ifmfsvl.Sieif;siPATENT; OFFICE JAMES M. CRAWFORD, or nE'rRorr; Po-RA'TION; 0FnEmRomrMIcHIGAN, A -con-Polmanoir.orv DELAWARE MlCHIG-AN,

ASSIGNORT'O GENERJ MOTORS coR- METHOD F suPRLRMRNrING'VTHE FRicrIoNAir.REsIsrANcnoF RELATIVELY MovARLE MEMBERS v Applicationfiled July 2,

lhis'invention Irelates to a centralizer for brakes, and'morelparticularly to a process for providing a predetermined resistance tothe relative movements of theparts of such a centralizer. The invention,while designed especially for the purpose stated, will be found. usefulin other relations.

An object of the invention is to provide a process for' producing anarticle .having movable parts, the relative movement of which is to befrictionally resisted by `a predetermined force. As a further object,the process secures the predetermined resistance to relative Vmovementof the parts'of the article by giving to a resilient means associatedwith said parts a predetermined degree of resiliency. As a furtherobject, the process insuresuniformity in the case of a plurality ofarticles, each having a predetertheir relatively mined resistancebetween movableparts. v Other objects' and advantages will be obviousfrom a reading of the following description and an examination of theaccom@ panying drawings. In'the drawings: I Figure l illustrates anapparatus partly in elevation and partly in section whereby the processmay be carried out.

Figure 2 is a section 'of the completed article, the section being online 2k2'of Figure l.

Figure 3 is a top plan viewof the article with the cover plate removed.

Referring byreference characters to the Y several figures, numeral 5represents thebase let() of the apparatus designed to' secure byitsoperation uniform pressures in rubber blocks, used in connection forvehicleV brakes. Ingsuch brakes, a box or the like 7 has openings 9vinflange's 11 whereby it may be clampedto the fixedv or backing plateofja brake. This boX hasaligned 'open'-v ings 13 and 15,'one of lwhichi'sonV that side adjacent the flanges' 11 and theother on the oppositeside. L Nithin the 'boX isa cylindrical-member 17A which, as ,clearlyshowny in Figure' 3, Vis rotatable within thebox; The member`17j istransversely apertured asat 19 and provided 'with a" bushing V21 torotatably `to accommodate the with centralizing devicesv 19,28.'`,serial no. 289,967.

cam carrying shaft of a vehicle brake. Itl

will be understood, of course, that the cam on this shaft is'to belocated'within the brake drum and engage the ends of they brake band orthe brake shoes. the' openings 13 and 15 aresuliciently large member 17carrying the projecting camshaft; Beneathmember l7`is a bearing ring 23between the fixed boX and-the rotatable member117. On the'opposite side,the member 17 is recessed and'in the recess is locatedmeans tofrictionally engage withthe adjacent face of the boX and-resist tooyfree rotary moverotary movement of the yt will be seen, too,`thatmentiof the vpartl7. VIt'will be understood that in the` action ofthebrakeit is desirable that the camshaft shall be not only rotatable onits axis,'asin bushing 21, but that the cam may have a limitedcircumferential movement in the drum. `It'l is to give that'movementthat part 17 is mountedrotat#v f ably inbox 7. It isto resist too freemovement of member 17 inthe vbox thatthe resisting means is locatedinthe recess of member 17.

member 17 relative to boX7 in thefcaseof the several brakes should beequally effectivev to secure uniform brake action. It is,t herefor`e,proposed to use a block of rubber 20, or the like, -in the recess ofmember 17 and to interpose a disc of metal 22 upon the rubberto en-`gage the walls of the `boX, the rubberito exert uniform pressure on thedisc. `The purpose of the apparatus herein disclosed is'to deform thedisc 22 and therubber blook`20 toqsuch an extent that,`in the case'of aplurality of such articles, theremay be thersame resiliency imparted tothe'rubber block 20 \and,'in con- Vto rock thecam, Y

pressure neglecting" exceedingly great retina' Vment as touniformityinresilient character;

istics or dimensions.

75l `The means to control the movement of 2 f v l 1,833,415

Upon base 5 is mounted a ivorksupport 25Y y suitably carriedv acentralizer upon which is Any assembly, as shown in the drawing.

' suitable means (parts 27 rbeing illustrative merely) to hold the Workony support 25,1'nay be used. The support 2521's adjustable by means ofa threaded rod 28 positioned by an adjustable member 29. The upperend ofrod v28 'haszaball 29 vlocated VWithinasocket B1l secured tothe'undersideof support '2.5 by fastening means 33.

` Tlieba'sef 'hasan arm 35 arched upvva-rdly over the Work support. vThetop 37 of the-arm Y is recessed 'as at 39 to receive therein a cir-vcular disc 41. This disc carries a plunger 43 operable through .anopening 45 in thelower part the top portion 37. Between the recess 39.and the; opening 45 is apoclret 46 housinga coill spring 47 seatedinthe pocket and .engaging .the disc .41.eXertingupWard pressure onsaiddisc. Tolimit theupvvard movement' of the disc under the influenceefr-spring 47, thevplungerzl?) earriesadjustingnuts 4.9y

engaging the top 'member .The plunger terminates in .a rounded end 44,Whichmay enter an opening 51 in the top 53 of the box 7.

This top is removblyassociated-with the box `for the purpose of assemblyand isheld in position ,by fastening means 55.

lSecuredlto the-,top 37 ofthe basecasting is .a housing 57, there beingfastening bolts 59. Clamped betWeenthe-top 37 and the flangesofthe-*housing andheldbybolts59 is A:a diaphragm` 6l. rThis diaphragmis. engaged by .disc `41,' asfshown. The housingis to carry theoperating `vmeans =by :which 4ra predeten Y minedpressureis.given thevrubber blocks of thecentralizer. ,Theh using'is covered by a 'Iclosure` member 63 *40 secured *by .fastening Vmeans'65. l l

, Housing 5,7. isrecessed in its bottom-portion,

' as at`66,said recess being bounded by .a-.Wall

67Qand by,thediaphragmfl. The wall `67 carries afvalve cage69 littedinto .an opening inran intermediate .partfthe-reof.'` rlhe valvecage'hasfa seat and lateralopenings,

Wherebyftheramay be apassage-.betiveen recess 66 and the chamber.Within-'the housing The communication may #be closed 'by valve7 5earriedbystem f7 7 guidedby the top 79 offthe cageand bythefcovermember163, as shoWnin thedraWing-s `A spring 81 surrounds thestem ,77outside 5the cover and .is vin abutmentwith .the cover and `with. a lug83or-a lever Bspivotedat A86.*00 a lug 87.0111

the. cover 63. y The .spring tendsfto -raisethe stem andthevalve7 5yandopen the communi.- cationlbetweenthe recess 66 and the chamber of-thehousing This spring maybe overcome by inanualpressure 4appliedto theend of the .lever whereby-the Yvalve -may Abe closed. A

, cond-uit 89,eXtends from the recess 66 `up l through'tlkie housingandfcoverztoav gage 91 which; serves Vt'ogindicate thepressure conditionWithin the recess 66. f f

g under ,the influence of. springs 97 and in a remote Wall of thehousing. This shaft mayfcarry gear 93 and gear 95 may be driven byfgear.93. "Tvvof'c'onduit'sllO andlO f extend .fromithe casin ggto' the,`housing chamber and "to the recess respectively.

"103 servesaasanfinlet for thepump and-conjd-uit-105as an outlet. Theaction of the pump is to draw fluid from thehousing chamber anddise'harge'itintoj the recess. lVhen the valve is open, the fluidreturns throughthe cage openings. When. the .valve 7 5.is c1osefd,the

pressureis. delivered to the fluid Within re-l This pump may be con-Conduit cess 66and ,th'efdiaphragm ,and disc 41 de scend and -the,plunger 43,: exerts pressure on disc 22. Y f y The shaft 101 frnay. be.driven in any .pre-

ferred manner. There is shown apulley 107 carried by shaft 101 and Vabelt109for driving the pulley.

Topredetermine the maiimum pressure Yto be applied totheplunger,a-.relief valve mayv be used. ,Y Such'a .valveis shown in Figure 1 inthebasel'wof-the housing.l A pluglll is inserted in the base. .It has anopeningll and :valve seat .1.15. The plug has. lateral Openings117 andan integral Y.valve stem guide-119 .for a valve -stemj121. l The valve123 carried by thestemengages the valve seat 12,5. These springs havetheir ends connected respeca-nd to the ends of the cross-head 129 vheldvby nuts 131 or the-.equivalenten the valveistem.A

The springs serve, by their tension, to hold the valve seated. Thetension of thev springs is overcome when.r a predetermined pressure 1sYapplied by thepump Within the recess 66 4 and the fluid is thereaftercirculated, even though the manually operated .Valve 75 remainsclosed.'` A i" In operation, lthe parts lof thefcentralizer tively toarms 127.projectingfrom the plug :los

are assembled, and the Yassembly is placed ,on

the support 25. luso assemblingthe parts, blocks of-rubbermaybe usedWhich-areinot all alike in dimensions or characteristics.. The Y. j

upon the-pumped .fluid enters recess 66 and depresses the plunger. VTheend of` the plunger 43-engagesthe disc, bends .it )subs tantiallyitorthe shape rshown in Figure 2, andthe rubber is deformedlandexerts. aforce vthrough 1 the margin ofnthe disc .and upon the box cover. Theoperator may watchfthe gage,

andvvhen a predetermined pressure is reached'k he mayrelievethepressure.'V Should-.befall to so relievethe pressure and if the.lapparatus lever is .pulled down toclose valve-7 5 Wherej is `supplie-.dwith therelief-.valve shownin-the y drawings, this valveWillautomatically permit fluid. circulation 'and -stop-the V'plu-ngerono at a predetermined point in its downward movement. The movement ofthe plunger permanently bends the plate 22 and deforms the rubber, theelasticity of the latter thereupon makes of it a resilient memberpressure between the member 17 and the box 7 which pressureresilientlyresists the rotary movement of member 17 within the box.

I claim:

l. The method of supplementing the fric-` n tional resistance to therelative movement of two members consisting in assembling said membersfor relative movement, positioning between said members an elasticdeformable mass and a relatively inelastic deformable element, forciblyand permanently deforming fthe latter element, and through thedeformation of the latter deforming theelastic means, whereby itselasticity is effective to cause frictional resistance to the relativemovement of said members.

2. The method set forth in claim l, the deforming force being'appliedsubstantially centrally of said deformable element and said elementperipherally applying the resiliency of said elastic niass'to one ofsaid members Y 4. The method of applying a braking force to resist theVrelative movement of two frictionally engaging members comprisingassembling said members for relative movement, assemblingV with a Erstone of said members a non-metallic deformable elastic mass, and incontact therewith and for engagement with a second one of said members adeformable inelastic element and thereafter simultaneously deformingsaid element and mass under the influence of a predetermined pressure.

In testimony whereof Irafix my signature.

JAMES M. CRAWFORD.

exerting

